This invention relates generally to traffic control systems, and more particularly, to traffic control systems providing wireless communication of information between a plurality of traffic control signs.
Drivers traversing roadways in their vehicles are provided with many different traffic control signs having traffic control information, such as, for example, sign-directed cautions, alerts and information. This traffic control information is typically provided along and above the roadway to control traffic, as well as display other useful information (e.g., next rest area). For example, sign-related information may include information on permanent signs relating to speed limits, dangerous intersections, sharp turns, construction zones, railroad crossings, school zones, stop signs, detours, merges, etc. Additionally, and for example, sign-related information may include manually-held signs alerting drivers of construction, lane changes, accidents, detours, etc. Further, sign-related information may be provided on vehicles, such as, for example, a stop sign on a school bus, a slow vehicle sign on slow moving vehicles and a wide load sign on larger vehicles. This sign-related information is intended to control traffic, prevent accidents and provide drivers with useful information.
The size, shape, color, and positioning of traffic control signs to provide sign-related information is typically selected to maximize visibility by drivers. However, external factors may affect the effectiveness of providing this information to drivers. For example, elderly drivers may not see or process the information on a traffic control sign as readily as younger drivers. Further, sleepiness and/or driver fatigue may result in a loss of attention to the information provided on traffic control signs. In other instances, environmental factors may affect the effectiveness of providing this information. For example, hilly terrain or outgrowth of plants and trees may obscure traffic control signs from a driver, thereby resulting in the information on the sign never being seen by a driver or seen too late. Weather conditions also may obscure traffic control signs and, for example, limit the distance from which a driver can view the information on a sign.
Additionally, depending on the driver and vehicle, the placement or positioning of traffic control signs may not provide drivers with enough warning regarding an upcoming condition (e.g., sharp curve or lane closed ahead) to allow the driver to properly react to the information posted on the traffic control sign. Also, the spacing between traffic control signs may not allow for proper response by a driver, for example, if the traffic control signs are too close together or too far apart. Further, there is typically no means to provide information to a driver if the driver, for example, does not see a traffic control sign (e.g., driver fails to see a sharp curve sign) and passes the sign. Also, there is typically no means to provide information to a driver relating to a traffic control sign based on upcoming conditions (e.g., work zone ahead posted on a traffic sign with a stopped vehicle in the work zone). Many traffic control signs include permanent posted information that provide only static information without the ability to provide updated information to the driver.
Thus, the effectiveness of traffic control signs to provide information to drivers is often reduced by factors or circumstances such as the placement or positioning of the signs, driver incompetence, driver age, indifference or inattention, roadway limitations or impairments and/or weather conditions. Reduction or limitation of the ability to view these signs, as well as improper positioning of these signs, decreases the effectiveness of the signs and may increase the likelihood of accidents or other undesirable or unintended consequences. Further, many signs do not provide adequate notice regarding upcoming conditions because of the permanent nature of the signs.